Cryogenic behaviour of optoelectronic devices for the transmission of analog signals via fiber optics

The transmission of analog signals via fiber optics is a subject of interest for applications with detectors operating at cryogenic temperature, at ground or on space borne instruments. For those detectors, both thermal and galvanic decoupling shall be required. For a better understanding of the cryogenic performance of cooled optoelectronic devices, we have investigated an infrared AlGaAs LEDs, a Si p-i-n photodiode, a Si photodiode, and an avalanche photodiode (APD). Results of a study related to the photodiode's dark currents at low temperature is presented. In fact, we have clearly measured a strong reduction of the dark current when these devices are cooled down